The present invention is directed to a simple, economical and effective measuring tool for measuring multiple angles between flat angularly related surfaces and particularly relates to a measuring tool for transferring those angles to other surfaces whereby the tool becomes a template precisely corresponding to the measured angles.
As architects, draftsmen, carpenters and others have long known, there is a need for measuring angles in a three-dimensional sense. For example, where gabled roof lines meet, there is a need to be able to measure the angle between the two flat surfaces with reference to a datum, e.g., a true perpendicular or horizontal. The angle to be measured thus extends angularly to each of the horizontal and vertical and is therefore a three-dimensional angle relative to the datum. After measuring, there is the further need to transfer the angle to other work or use the instruments as a template, for example, to adjust a saw blade for making cuts at multiple angles.
In accordance with the present invention, there is provided a measuring tool for measuring angles between flat angularly related surfaces which are both angled relative to a horizontal or vertical datum surface. More particularly, the tool includes a pair of measuring sections which are hinged one to the other at mating ends for pivotal movement in a plane about the hinge axis. Each measuring section includes a flat plate which is mounted in that section for pivotal movement about an axis in the plane and normal to the hinge axis of the measuring sections. To mount the plate for pivotal movement about the normal axis in each measuring section, there is provided a rod which projects from a hinge element of that section and which lies coincident with the axis normal to the hinge axis. A sleeve is rotatably mounted about the rod and mounts the plate whereby the plate is pivotal about the rod. The plate is also locked in adjusted angular positions about the rod. To accomplish this, the end of the rod distal to the hinge element mounts a threaded locking element. By threading and unthreading the locking element relative to the rod, the sleeve is frictionally engaged and disengaged between the base of the hinge element and the locking element whereby the plate may be selectively locked and unlocked in selected adjusted angular positions about the normal axis.
Each hinge element includes a surface for mating with a corresponding hinge element surface of the other measuring section. A screw-threaded pin passes through openings in these mating hinge elements in forming the hinge axis. A knob threadedly engages the pin on the opposite side of the hinge elements whereby the hinge elements may be releasably locked one to the other, hence enabling the measuring sections to be locked in selected angular adjustment relative to one another about the hinge axis.
Additionally, the measuring tool hereof mounts each plate for linear sliding movement in a direction generally parallel to the normal axis about which the plate pivots. Thus, the plate is slidable into selected adjusted positions relative to the sleeve and may be locked in such positions. It will be appreciated that the plate includes measuring indicia, for example, in the English or metric systems, for measuring distances.
To use the measuring tool hereof, the locking knobs are loosened so that each plate is pivotally rotatable about the normal axis and each measuring section is freely pivotal about the hinge axis. The tool may then be placed against the flat surfaces to be measured, with the plates lying flush against such surfaces. The knobs are then tightened to lock the hinge elements one to the other and each plate to the corresponding hinge element. Thus, the angle is measured by the setting of the measuring tool in a three-dimensional sense. By locking the tool in this position, the tool may be removed from the measuring surfaces and transferred to work and the identical angle measured by the tool may be transcribed onto the work.
The angles between the plates may be transcribed onto the work and then the relative angular relation of the plates about their long axes may be transposed to the work by transcribing across the end of the plate onto the work.
The tool may also be used as a template, for example, when setting up a saw blade of a radial arm saw to make simultaneously a mitre and bevel cut. To accomplish this, the tool is applied to the flat surfaces to be measured and the plates and angles between them are locked. The tool with its measured angles is then placed on the saw table and the blade is adjusted in both the meter and bevel angles to correspond to the measured angles, hence exactly replicating the measured angle in the next saw cut.
In a preferred embodiment according to the present invention, there is provided a tool for measuring angles between surfaces, comprising first and second measuring sections, each section having a measuring plate extending in a predetermined plane, a hinge element for pivotally securing the sections one to the other and defining a hinge axis for the sections, means pivotally mounting each plate and the hinge element relative to one another enabling each plate for pivotal movement about an axis generally normal to the hinge axis and first means for locking the plate relative to the hinge element in selected angular positions about the normal axis and second means cooperable with the hinge element for locking the sections in selected angular positions about the hinge axis whereby the measuring plates are angularly adjustable about the hinge axis and about axes generally normal to the hinge axis.
In a further preferred embodiment according to the present invention, there is provided a method of measuring angles between angularly related flat surfaces with a tool having a pair of measuring sections pivoted one to the other about a first axis, with each section having a measuring plate pivotable about a second axis normal to the first axis, comprising the steps of abutting the plates against the respective surfaces by (i) pivoting the sections relative to one another about the first axis into angularly adjusted positions relative to one another and (ii) pivoting at least one of the plates into an angularly adjusted position about its second axis to locate the plates flush against the surfaces and locking the sections and the plates in the respective angularly adjusted positions.
Accordingly, it is a primary object of the present invention to provide novel and improved apparatus and methods for measuring multiple angles between flat surfaces in a three-dimensional sense.
These and further objects and advantages of the present invention will become more apparent upon reference to the following specification, appended claims and drawings.